Look out, Dropbox. The large-file sharing system already had competition for in Google Drive, Microsoft's SkyDrive, Amazon Cloud Drive, Mozi and others. Now Dropbox faces a new challenge in peer-to-peer file sharing from BitTorrent. The new service, called BitTorrent Sync, automatically syncs files between computers via secure,
distributed technology. And, by the way: It's free (for now), no matter how large the files.

BitTorrent announced Sync in its blog last week and the new service is now in pre-Alpha testing. "We like it when things work together," said the blog. "So we've been working on a new distributed syncing product to help manage personal files beween multiple computers.

Break It Up And Send It

San Francisco-based BitTorrent was founded in 2001 by Bram Cohen, who currently serves as chief scientist and formerly worked at MojoNation, maker of that breaks up and encrypts files for distribution. His bio on the BitTorrent site says that concept of breaking up and encrypting files served as the inspiration for his development of BitTorrent.

Today, BitTorrent's P2P file-sharing protocol is used by an estimated 150 million active users. It works by reducing the server impact of distributing large files by redistribuitng the load to many hosts to upload and download simultaneously. Users create a file called a torrent, and it is broken up into components. After the initial transfer, a sender can easily send a copy once to multiple recipients.

Sync Testers Wanted

Regarding the search for testers, BitTorrent's blog says, "[W]e're hoping that users like you can help us build something sick. If you're comfortable using early, incomplete software, and if you're committed to helping us figure out a better way to sync, we want to hear from you."

The service is initially open to a limited number of testers who can fill out an application via BitTorrent's Labs page. The blog post includes a screen shot of the SyncApp, showing a list of files, devices and uplink and download speeds.

There's a forum attached to the blog for testers to ask questions and share feedback. One early poster suggests that the folks at BitTorrent meant to say, "help us build something slick" rather than something "sick." Chalk it up to the generation gap. Whether it's "sick" (that's 20-something talk for "really cool") or "slick" -- the folks at BitTorrent hope Sync will make it big.

Competitive Watch

Dropbox may face more competition with BitTorrent Sync on the way, but likely sees no cause for immediate worry. Last November, the Dropbox founder and CEO, David Houston boasted that subscriptions had quadrupled to 100 million users in the past year, or 20 percent of the world's estimated cloud storage subscriptions.

Microsoft is also poised to see a boost in its SkyDrive service since it is integrated into the Windows 8 operating system, giving it an advantage over Dropbox, BitTorrent and others. Apple, too, has cloud integration in its products with iDrive.

Billions of Users Served

A report by IHS iSuppli's Mobile and Wireless Communications Service in November estimated that the potential for cloud storage is, well, sky high, expected to reach a half-billion users last year, and 1.3 billion customers by 2017. Most services begin with a freemium model, encouraging people to hoard data and media and then begin to charge for larger volumes.

BitTorrent does not currently charge for its services but has received venture capital from investors like Accel Partners, DCM and Dag Ventures. The hope is to someday profit from the installed base through ads, third-party software bundling or promotions (similar to Twitter's model). The company also takes donations.

BitTorrent's two main products are the original BitTorrent P2P file-sharing software and uTorrent, a lightweight client for Windows or Mac.